diff --git a/klibc/klibc/include/ctype.h b/klibc/klibc/include/ctype.h
index 2cb90a45d3..e1a25f3693 100644
--- a/klibc/klibc/include/ctype.h
+++ b/klibc/klibc/include/ctype.h
@@ -88,7 +88,7 @@ __ctype_inline int ispunct(int __c)
 
 __ctype_inline int isspace(int __c)
 {
-  return __ctypes[__c+1] & __ctype_space;
+  return __ctypes[__c] & __ctype_space;
 }
 
 __ctype_inline int isupper(int __c)